1. Field of the Invention
The field of the invention is medical devices for magnetic resonance imaging (xe2x80x9cMRIxe2x80x9d) and more specifically, medical devices having a contrast medium for enhancing MRI images of body tissues and devices.
2. Background
Medical devices are often inserted into the body of a patient. These medical devices include catheters, guidewires and other devices. After insertion of the medical device into a patient""s body, medical personnel may use imaging techniques to take images of the body tissue near the medical device. For example, it may be desirable to insert a catheter having an angioplasty balloon into the body and then image the blood vessel near the balloon in order to determine the appropriate placement of the balloon relative to a partial occlusion. Alternatively, one may want to image the blood vessel after the balloon has treated the partial occlusion in order to ascertain the effectiveness of the treatment.
Commonly used medical devices are often difficult to see on MRI scans because they fail to produce sufficient contrast with respect to the surrounding body tissue or structures and/or are too small to be readily detected. Specifically, this is true for foreign objects such as catheters which are introduced into the body. U.S. Pat. No. 4,572,198 appreciated this problem and stated that if the structural portions of the catheter are simply more hydrogenous than the tissue surrounding the catheter, the catheter is detectable, but a limit is placed on the available contrast. Because of the electronic noise that they introduce to the imaging apparatus, additional functional elements such as electrode wires and the like employed in U.S. Pat. No. 4,572,198 significantly degrade the magnetic resonance image often to the point of complete image obliteration. If it is usable at all, the resulting image would be clinically less diagnostic and would make accurate localization of the implanted catheter difficult if not impossible. This appears at best to be a difficult and tenuous solution to the problem.
To improve one""s ability to ascertain the position of the medical device within the body, the prior art has taken various approaches to improve the visibility of the medical device in the images taken. For instance, prior art medical devices have used materials within the devices and textures of the devices"" surfaces in order to increase the xe2x80x9ccontrastxe2x80x9d or visibility of the medical devices in images. For example, see PCT patent application WO 98/22022 by ITI Medical Technologies, Inc. and U.S. Pat. No. 5,154,179, issued on Oct. 13, 1992 to Medical Magnetics, Inc. Although prior art medical devices have used materials or textures to create xe2x80x9ccontrast,xe2x80x9d such prior art devices use the materials or textures to make the medical devices more visible during imaging. However, there is a need to improve the quality of images of the body tissue itself, and not just those of the medical device. The improved medical device explained in this patent specification satisfies that need by enhancing the quality of images of body tissues and the device. Also, there is an additional need to further improve the visibility of implanted medical devices.
The invention relates generally to a medical MRI device for insertion into a body, the device having an imaging sensor for receiving signals and a contrast medium for enhancing signals received by the imaging sensor. In an example embodiment, the improved MRI device has an imaging sensor located near the distal portion of the device and a contrast medium disposed within the body of the device and located adjacent the imaging sensor. In a second embodiment, the contrast medium of the improved MRI device is contained within a portion of the imaging sensor itself. The improved MRI device may be, for example, a catheter or guidewire. A plurality of contrast media may be used, as desired. The contrast medium enhances the quality of MRI images of the body tissue and medical devices.
A first, separate aspect of the invention is a medical device comprising an imaging sensor for receiving signals used to generate a MRI image of body tissue and a contrast medium within the medical device for enhancing signals of the body tissue received by the imaging sensor in order to generate an enhanced MRI image of the body tissue.
A second, separate aspect of the invention is a medical device comprising an antenna for receiving signals used to generate a MRI image of body tissue and a contrast medium for enhancing signals of the body tissue received by the antenna in order to generate an enhanced MRI image of the body tissue.
A third, separate aspect of the invention is a medical device comprising an imaging sensor for receiving signals used to generate a MRI image of body tissue and a contrast medium within the medical device and adjacent the imaging sensor for enhancing signals of the body tissue received by the imaging sensor in order to generate an enhanced MRI image of the body tissue.
A fourth, separate aspect of the invention is a medical device comprising an imaging sensor for receiving signals used to generate a MRI image of body tissue and a contrast medium within the medical device and adjacent the imaging sensor for enhancing signals received by the imaging sensor of the body tissue in order to generate an enhanced MRI image of the body tissue, where the contrast medium comprises gadolinium or a superparamagnetic contrast medium.
A fifth, separate aspect of the invention is a medical device comprising an imaging sensor for receiving signals used to generate a MRI image of body tissue, a reservoir in the body of the medical device, and a contrast medium contained within the reservoir for enhancing signals of the body tissue received by the imaging sensor in order to generate an enhanced MRI image of the body tissue.
A sixth, separate aspect of the invention is a medical device comprising an imaging sensor for receiving signals used to generate a MRI image of body tissue, a reservoir in the medical device, and a contrast medium contained within the reservoir for enhancing signals of the body tissue received by the imaging sensor in order to generate an enhanced MRI image of the body tissue, where the contrast medium comprises gadolinium or a superparamagnetic contrast medium.
A seventh, separate aspect of the invention is a medical device comprising an elongate body, an imaging sensor positioned on the distal portion of the elongate body, the imaging sensor receiving signals from body tissue, and a contrast medium within the imaging sensor for enhancing signals of the body tissue received by the imaging sensor in order to generate an enhanced MRI image of the body tissue.
An eighth, separate aspect of the invention is a medical device comprising an elongate body, an imaging sensor positioned on the distal portion of the elongate body, the imaging sensor receiving signals from body tissue, a reservoir, and a plurality of contrast mediums within the reservoir for enhancing signals of the body tissue received by the imaging sensor in order to generate an enhanced MRI image of the body tissue.
A ninth, separate aspect of the invention is a medical device comprising an elongate body, an imaging sensor positioned on the distal portion of the elongate body, the imaging sensor receiving signals from body tissue, a reservoir having first and second compartments, a first contrast medium contained within the first compartment, and a second contrast medium contained within the second compartment, the first and second contrast mediums enhancing signals of the body tissue received by the imaging sensor in order to generate an enhanced MRI image of the body tissue.
A tenth, separate aspect of the invention is a method of imaging body tissue from within a body comprising the steps of inserting a medical device with an imaging sensor into the body adjacent the body tissue to be imaged, positioning a contrast medium adjacent the body tissue to be imaged, and imaging the body tissue.
An eleventh, separate aspect of the invention is a method of imaging body tissue from within a body comprising the steps of introducing a selected contrast medium into a reservoir of a medical device, inserting the medical device with an imaging sensor into the body adjacent the body tissue to be imaged, positioning the reservoir of the contrast medium adjacent the body tissue to be imaged, and imaging the body tissue.
A twelfth, separate aspect of the invention is a method of imaging body tissue from within a body comprising the steps of introducing a first selected contrast medium into a first compartment of a reservoir of a medical device, introducing a second selected contrast medium into a second compartment of a reservoir of the medical device, inserting the medical device with an imaging sensor into the body adjacent the body tissue to be imaged, positioning the reservoir of the contrast medium adjacent the body tissue to be imaged, and imaging the body tissue.
A thirteenth, separate aspect of the invention is a method of imaging body tissue from within a body comprising the steps of inserting a first medical device with an imaging sensor into the body adjacent the body tissue to be imaged, introducing a second medical device adjacent the body tissue to be imaged, the second medical device containing a contrast medium for enhancing the image of the body tissue generated from signals received by the imaging sensor of the first medical device, and imaging the body tissue with the first medical device.
The invention may include any one of these separate aspects individually, or any combination of these separate aspects.
Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.